Apparatus for catalyst regeneration



Sep 6, w49.

Filed. June 20, 1945 L. F. STRADER APPARATUS FOR CATALYST REGENERATION 6Sheets-Sheet l Sept. 6, 1949. L. F. sTRADER 2,480,887

APPARATUS :ff-'OR` CATALYST REGENERATION Filed June 20, 1945 6Sheets-Sheet 2 @apt 6,1949. 1 F. STRADER APPARATUS FOR CATALYSTREGENNATION 6 Sheets-Sheet 3 Filed June 20, 1945 e o o o 0 0 0 ooo oo sce a ooo o /7 o o o o o o ooo ooo O00 O00 ooo o o o ATTO R N EYS L. F.STRADER v 40,@87

APPARATUS FOR CATALYST REGENERATION Spt. '6, w49.

6 Sheets-Sheet 4 Filed June 20, 1945 w E@ m m5 Mw ATTORNEYS pt 6, E949.1 F. STRADER 29480 87' APPARATUS FOR (L'IAIJI'S'1 REGENERTION Filed June20, 1945 6 Sheets-Sheet 6 INVENTQR eqy grader ATTORNEYS Patented Sept.6, 1949 UNITED STATES PATENT` FFICE APPARATUS FOR CATALYST RE GENERATIONLeroy F. Strader, Long Beach, Calif., assignor, by mesne assignments, toHoudry Process Corporation, Wilmington, Del., a corporation of Dela-Walle Application June 20, 1945, Serial No. 600,475

2 Claims.

'of which spent catalyst is charged, from the lower end of whichregenerated catalyst is discharged through a central discharge port andin which a charge of catalyst moving downwardly through the kiln isblown with air to burn off the coke. In such kilns it is important thatthe movement of lcatalyst downwardly through the kiln be substantiallyuniform across the entire shaft throughout the combustion zone.Otherwise irregularities in burning occur, the eiliciency and capacityof the kiln are reduced, and frequently irregularities in movementbecome abrupt or periodic or both imposing severe stresses on the kilnstructure and adding to the degradation of catalyst resulting fromirregular burning.

To distribute the downward flow of catalyst across the shaft, it iscustomary to arrange one or more horizontal bailies, collector plates,across the shaft above the central discharge port, the lowermost baillebeing provided with a plurality of sub-ports spaced symmetrically aroundthe axis of the shaft and discharge port, the next above being providedwith groups of sub-ports, each group being positioned symmetrically withrespect to one of the ports in the next lower baie, and so on. Such'multiple division and subdivision of the flow of catalyst mightaccomplish fairly uniform distribution of flow if all of the catalystpellets were perfectly symmetrical, of uniform size and density, and ofuniform surface condition, but in a real kiln irregularities appear,irregularities such as fines and fragments and variations in density andsurface, which involve irregularities in flow. Unlike a liquid, a piledsolid, asin the piles beneath each sub-port in the baiiies of thearrangement just described, does not ow smoothly or continuously.Instead, the piled solid flows in a series of slides or avalanches; asthe angle of the surface of the pile in any particular region exceedsthe angle of repose a slide eventually occurs until the angle of thesurface in that region is somewhat less than the angle of repose and theremoval of 'material by a slide or slides in lower regions produces, inthe same manner, slides in higher regions in the pile. The effect issomewhat like the progress of rain drops downwardly across a largeWindow pane in 'a rain fall too light to wet and wash the pane exceptthat it is upside down, the rain drops initiating successions of runsfrom above whereas successions of slides of the piled-solid areinitiated from below; v The region involved in any one slide may besmall or may be large, depending on the integrated effect of variablessuch as those mentioned. If

the slides are short and frequent and Well distributed, the effect mayapproximate an equivalent of uniform flow and uniformdistribution offlow, but if irregularities occur they tend to be cumulative andfrequently involve ultimate disturbances of destructive magnitude,disturbances which impose severeA stresses on the kiln structure andwhich involve degradation of the catalyst. Long and infrequent slidescannot be tolerated even though fairly regular because of the forcesinvolved; the catalyst flow through such a kiln may amount to as much astons per hour or more and the charge at any moment may substantiallyexceed 150 tons. Y

To suppress one type of irregularity of flow in such kilns of squarecross-section, it has been' proposed to arrange a horizontal bailleacross the shaft, below the combustion Zone and spaced above the'centraldischarge port, provided with four sub-ports each positioned centrallyof one of four squares constituting a crossing quarter of the bale andto arrange four discharge tubes beneath the baille, each positioned toreceive catalyst flowing downwardly through one of the sub-ports andeach extending vertically downward from the baffle for a minimumdistance of two, or better three, diameters and then inclining towardthe vertical axis of the shaft and central discharge port for a minimumdistance of two, or better three, diameters at an angle steeper thantheangle Yof repose of the catalyst to a terminal opening short of thataxis but closer to the axis than the sub-port with which that tubecommunicates. Additional collector bailes may be arranged, as inconventional practice, above the baille associated with-thedischarge'tubes just described. y e I have found that the combinationof'such discharge tubes with the sub-ports of the lowermost collectorbaffle in such kilns is improved, in terms of the uniformity of catalystflow attained in application, by the provision of means for regulatingthe relative flow through each of the discharge tubes. This I accomplishby providing gates, corresponding in numberv to the discharge tubes,adapted to, move vacross the several terminal openings of the dischargetubes with an independent operating extension for each gate adapted tomove the gate across and position it with respect to the terminalopening o the associated discharge tube from a point without the kiln. Ihave in this manner been able to accomplish regularity of the lrelativeflow through the several discharge ltubes without introducing any newelement itself tending to disturb uniformity of flow. My invention isimeiul in connection with vertical shaft kilns of square cross-section,but it is also useful generally in connection with vertical shaft kilnsof ani7 crosssection provided with a iina'lcollector baille providedWith a plurality of sub-ports 'spaced 'symmetrically around the axis 'ofthe yshaft 'and Adisl charge port.

The accompanying drawingsillustrate apparatus embodying my invention.Although diagrammatic and conventional, these drawings are @in generalof scale proportions although in some instances, notably in Figure 2,-pa-rts -have been spaced to promote clarity -of illustration. Referringvto these drawings:

Figure 1 is 2a riiow diag-ram of a cracking system embodying ia kiln vatthe left of -the drawing,

of the type Ito Ywhich my invention relates,

Figure 2 is an elevation of a kiln such as that illustrated in Figure i,l

Figure 3 -is an enlarged section of the lower part 'of thefkilnillustrated lin Figure 2, on the 5,

line 3-3 `of Figure 4,

Figure 4 is an enlarged section of the lower part -of the kilnillustrated in Figure 2 taken at right angles to the sectionconstituting Figure 3, on lined- 4 of Figure 3,

Figure -5 is a section online .5 5 .of Figure 3,

Figure 6 isa section on yline B--E of Figure 3,

Figure 7 `is asection-oniline 1--1 of Figure 3,

, Figure 8 is -an enlarged section Aon vline 8-8 of Figure 3,

Figure 9 .is an enlarged .fragmentary .section on line 9-9 of Figure :8,kand v fFigure 10 1is -a yfragmentary section of any lof the -beam`ducts vassociated with distributing or collecting Vtroughs lin theseveral sections illustratedin Figures Sand '4.

Referring .to Figure l as .a .diagram lof the cracking operation as awhole: A charge of catalyst is maintained 'in a reactor 20, theregenerated catalyst ybeing Asupplied from storage chamber 22 throughconnection 2l and spent catalyst being discharged through connection 23.The temperature in tlie .reactor mayapproxirnate, for-example, 90W-975F. .andthe pressure `in the reactor .may approximate 6--l0 vflbs. persquare 5,.

inch gauge. lConnection '2| vis 4made long enough to serve Ias a seal.The hydrocarbons to be cracked `are introduced into the reactor as avapor mixture through connection .2`4. Steam to strip the spent catalystleaving the reactor of vapor-izable material is :introduced throughconnection -25. The cracked hydrocarbons .together with .any `unoracked-material .and the stripping steam 'leave -the reactor as a vapor.mixture through connection 2.6. :Spentfcatalyst is lifted to theitop-of the :kiln 2.1 K.bymeans of bucket elevator i213, `ventering thekiln through connection 42, Any rfresh-catalyst .required to maintainVthe volume of catalyst .in -circulation in Vthe system is introducedthrough connection 29 and 'lifted to the vtop of the kiln 251 by meansVof elevator 28 together withthe Aspentcatalyst. The'catalyst movesdownwardly through the'kiln through .a `series of bodies nin a.corresponding series of zones .through which air 'is blown by means 'ofconnection 36.

dblower 3U and distributing ducts or manifolds 3| with appropriateconnections to each of the several zones. The products of combustionescape from each of the several zones through ducts or manifolds 32,ultimately escaping through stack 33. The regenerated catalystdischarged from the lower end of thekln through connection 3ft is liftedto the catalyst storage chamber 22 by means of bucket elevator 35. Partof the regenerated catalyst passes from the head of elevator 55 directlyto chamber 22 through Another part, E70-10% of the total for example,passes, through connection 31 to an elutriator SS. In this elutriatorthis diverted part oi the regenerated catalyst falls through a risingstream of part of the gases passing to the stack, the fines beingcarried o with the Vgases and the coarser material returned throughconnection 39 to the foot of the elevator 35. Or, the coarser materialmay be returned, through an appropriate seal, directly to the top of thekiln. Before escaping through the stack 33 the products ci combustionpass through .a series of cyclone separators it `in which -ines ycarriedout of the elutriator together with any1-"mes carried out oi the kilnproper are separated .and discharged through connection 4l. The kiln,the catalyst storage chamber, the reactor, the velevators and theseveral connections .through which the catalyst passes are thermallyinsulated to minimize heat loss. By passing fresh ycatalyst through thekiln `as it enters the system, such fresh catalyst is brought to thesame Vtemperature as the bulk of the circulating catalyst before Iitenters the catalyst storage chamber .or Athe reactor.

Referring to Figure 2 as anillustration .of .a kiln of the type to whichmy invention relates: The kiln comprises a rectangular thermallyAinsulated and refractory lined shell 43. 'To Ypromote uniformdistribution of the catalyst over a horizontal section of the kiln, adistributor plate @f carrying nine distributing tubes 45 is arranged atthe upper end of the kiln, and to promote uniform now of the catalystdownwardly through the kiln a series of bailles lor collector plates 46,lil, B and i9 each carrying `appropriately arranged distributing portsor tubes is provided .in the lower part of the kiln. 4A .horizontal.grid S is arranged above the baffle 4E and .below the combustion zonein the kiln. This grid is constructed of a plurality of deep and .narrowspaced bars Sl extending entirely across thesha'ft. 'The several bars Qimaking up the vgrid 'Sil .are supported in position by a series oftransverse spacer and support bars 32, to which the 'bars 9i are welded,the spacer and support bars .92 in turn being supported from plate '46by legs atappropriate intervals. In operation, spent'cata'lys't ischarged into the upper .end o1 .the 'kilnfthrough connection ft2 andregenerated `catalyst iis discharged from the lower end of the kilnthrough connection 36, the kiln "being maintained substantially full oicatalyst'between the lower'ends of the distributing tubes 5 and thedistributor plate 48. This charge of catalyst is divided into ten bodiesby nine groups of tubes 51, 52,'53, 54, 55, iiii, El, 5t and 5- tiroughwhich a cooling `mcdium lis circulated, each oiV these Ybodies Lbeingwithin a zone independent of the'othersfforcontrol purposes. Another'anda somewhat larger group of cooling tubes '50 is arranged beneath thetenth body.Y For convenience of reference these several zones are`numbered vin Figure '2 (and in `Figure 3), the zone through which thecatalyst rst passes being numbered I and the zone through which thecatalyst last passes being numbered Ill. A grid of distributing troughsfor introduction of air is arranged centrally of each zone and isconnected to the air manifolds 3l through beam ducts 14. A pair of gridsof collecting troughs is arranged above and below these distributingtroughs in each zone and is appropriately connected to stack manifolds32 through beam ducts 89. Valved connections are provided forintroducing steam, from manifold 60, into the grid of distributingtroughs in each of the ten zones as may be required. Valved connectionsll and 72 are also provided for introduction of steam, from manifold 60,into the uppermost grid of collecting troughs in zone I into the stackmanifolds 32 as a cooling agent, or, in an emergency as a smotheringagent. The several connections between the manifold 60 and the severalzones may also be used in an emergency to introduce steam as asmothering agent.

Referring particularly to Figures 3, 4, 8 and 9 as a more detailedillustration of the embodiment of my invention in a k-iln such as thatillustrated in the drawings: The shaft of the kiln illustrated is squarein section. A central discharge port 94 is provided at the lower end ofthe shaft for discharge of regenerated catalyst to connection 34. Theseveral horizontal baffles or collector plates 46, 41, 48 and 49 arevertically spaced in the shaft at the central discharge port 94, each ofthese baiiles being provided with discharge ports or tubes, as shown.The lowermost baille 49 is provided with four sub-ports 93 eachpositioned centrally-in one of four squares constituting a cornerquarter of the baille (see Figure 7). Beneath the balfle 49 I arrangefour discharge tubes 95, each positioned to receive catalyst flowingdownwardly through one of the subports 93. Each of the four dischargetubes 95 extends vertically downward from the baille for a minimumdistance of 2, or better 3, diameters, (of the discharge tube) and theninclines toward the vertical axis of the shaft, and of the centraldischarge port 94, for a minimum distance of 2, or better 3, diametersat an angle steeper than the angle of repose of the catalyst to aterminal opening 95 (see Figure 3) short of the shaft axis but closer tothat axis than the sub-port with which the discharge tube communicates.A gate 97 carried by a pair of arms 9.3 ipivoted at -99 is arranged sothat the gate 97 can be moved across the terminal opening 9@ of each ofthe discharge tubes. One of each pair of the arms 98 is extended to-form a crank |99 connected through .an extension IGI movable through agland E02 to a hand wheel ID3 located outside of the kiln. The lower endof the extension lill is threaded and the hand wheel |93,correspondingly threaded and secured to the lower end yof the gland 102by a collar permitting rotation without vertical movement, thus permitsthe operator to move the gate across the terminal 4opening and toposition it Awith respect to the terminal opening, thereby to secureeffective control of the relative flow through the several dischargetubes 95 associated with the four supports 93 in the lowermost baie 49,during operation. 'I'he gates 97 are arranged to be moved upwardly todecrease restriction of the terminal opening of the discharge tube fromthe position of maximum restriction at the lowest point in their travel.Since catalyst discharged through the terminal opening tends to pilebelow the terminal opening, and itself to restrict or stop the ow whenthe pile covers the terminal opening, or as much of that opening as isexposed by the gate, the gate, in any particular position when arrangedas illustrated, fixes the effective size of the terminal openingwithout, however, interfering with the catalyst flow below that opening.

I claim:

1. In a regenerating kiln comprising a vertical shaft, means forcharging spent catalyst to the upper end of the shaft and means fordischarging regenerated catalyst from a central discharge port at thebottom of the shaft, a horizontal balile spaced above the dischargeport, sub-ports in this baille spaced symmetrically around the axis ofthe shaft and discharge port, a corresponding number of discharge tubeseach positioned to receive catalyst flowing downwardly through one ofthe sub-ports, each of these vertically downward diameters and theninclining toward the vertical axis of the shaft and discharge port for aminimum distance of two diameters at an angle steeper than the angle ofrepose of the catalyst to a terminal opening short of that axis butcloser to it than the communicating sub-port, the

2. In a regenerating kiln comprising a vertical shaft, means forcharging spent catalyst to the upper end of the shaft and means fordischarging regenerated catalyst from a central discharge port at thebottom of the shaft, a horizontal bale spaced above the discharge port,sub-ports in this baille spaced symmetrically around the axis of theshaft and discharge port,

` a corresponding number of discharge tubes each positioned to receivecatalyst flowing downwardly through one of the sub-ports, each of thesedischarge tubes extending vertically downward from the baille for aminimum distance of two diameters and then inclining toward the verticalaxis of the shaft and discharge port for a minimum distance of twodiameters at an angle steeper than the angle of repose of the catalystto a terminal opening short of that axis but closer to it than thecommunicating sub-port, the improvement which comprises gatescorresponding in number to the discharge tubes, each gate being adaptedto move across the terminal opening of one of the discharge tubes,upwardly from the position of maximum restriction of the opening, and anindependent operating extension for' each gate adapted to move the gateacross and position it with respect to the terminal opening,- of theassociated discharge tube from a point. without the kiln.

LEROY F. STRADER.,

REFERENCES CITED UNITED STATES PATENTS Name Date Reynolds June 16, 19149Number

